[0] https://humanresearchroadmap.nasa.gov/Evidence/reports/BMed.... [1] https://link.springer.com/chapter/10.1007/978-3-642-30583-2_...
279 karma · joined February 23, 2018
[0] https://humanresearchroadmap.nasa.gov/Evidence/reports/BMed.... [1] https://link.springer.com/chapter/10.1007/978-3-642-30583-2_...
[0] https://humanresearchroadmap.nasa.gov/Evidence/reports/BMed.... [1] https://link.springer.com/chapter/10.1007/978-3-642-30583-2_...
> In this case, what’s dropped is &mut future1. But future1 is not dropped, so the actual future is not cancelled.
> why can't every proxy probe every [worker, not application]?
There are several divergent issues with this approach (though it can have it's place). First, you still need _some_ service discovery to tell you where the nodes are, though it's easy to assume this can be solved via some consul-esque system. Secondly, there is a lot more data than you might be thinking at play here. A single proxy/host might have many thousands of VMs under its purview. That works out to a lot of data. As you point out there are ways to solve this:
> One could reduce _average_ bandwidth a lot by having the proxies mostly send some kind of "send changes since <...>" or "send all data unless its hash is <...>" query.
This is definitely an improvement. But we have a new issue. Lets say I have proxies A, B, and C. A and C lose connectivity. Optimally (and in fact fly has several mechanisms for this) A could send it's traffic to C via B. But in this case it might not even know that there is a VM candidate on C at all! It wasn't able to sync data for a while.
There are ways to solve this! We could make it possible for proxies to relay each others state. To recap: - We have workers that poll each other - They exchange diffs rather than the full state - The state diffs can be relayed by other proxies
We have in practice invented something quite close to a gossip protocol! If we continued drawing the rest of the owl you might end up with something like SWIM.
As far as your second question I think you kinda got it exactly. A crash of a single corrosion does not generally affect anything else. But if something bad is replicated, or there is a gossip storm, isolating that failure is important.
Fly has a lot of interesting networking issues but I don't know that like, the actual routing of packets is the big one? And even in the places where there is bottlenecks in the overlay mesh I'm not sure that custom FPGAs are going to be the solution for now.
But also this blog post isn't about routing packets, it's about state tracking so we know _where_ to even send our packets in the first place.
I work on a database engine that uses parquet as our on-storage file format and we make liberal use of the custom metadata area for things specific to our product that any other parquet readers would just ignore.
What does this look like in practice? As you mentioned I know you don't really have any lateral control, but I imagine you can wait for it to overfly somewhere convenient to descend?
ALTER TABLE your_table ADD updated_at TEXT;
This is also relatively harmless, but now you have to figure out how to run this migration across your 100 databases, and deal with the case where maybe some fail, what do you do then? Rollback everywhere? But what if some users have already have rows that use the new column? Do you delete their data? Etc. Now consider a more complicated migration, maybe it renames a column, drops a column, adds a default value, drops an index, etc. You can see where problems might come from.That said I do really like your idea, I've gotten into sqlite a lot lately (I work on the database team at Fly.io), I'm just responding to you questions specifically about migrations.
EDIT: See this comment for an example on how to make the provider use the public endpoint https://github.com/fly-apps/terraform-provider-fly/issues/42...
EDIT EDIT: I pasted the wrong link, sorry about that.
And when gifted programs become screeners of affluence then there are going to be financially involved parents in the PTA which benefits the whole school. But if all of those parents end up at the "good" schools then those schools have considerably more funding (on top of the additional funding from the DOE) to allow them to actually educate their students. It is all a self reinforcing cycle that benefits a few and disadvantages many.
The problem is that in New York at least the gifted programs are the direct mechanism by which rich parents uphold the status quo of segregation. The gifted prgrams are not a proxy, they are a symptom. As I said elsewhere in this thread: we are looking for a fair allocation of resources to actually give schools the ability to meet every student where they are and to engage them wherever that is.
The fact that gifted programs would be needed at all is a failure of our public school system. Every school should have the resources to adequately engage and educate every student regardless of their academic starting point.
Sure! Yes! We are looking for a fair allocation of resources to actually give schools the ability to meet every student where they are and to engage them wherever that is. All teachers want to be able to meet kids where they are, wherever they are, but they don't have the resources to.
I am saying that. "Gifted" programs and the schools that house them eat up a sizable chunk of funding.